1. Field of the Invention
The present invention relates to a display device which can provide a virtual display image based on image information, such as display image on driving information to be produced on a window glass of motor vehicles, boats and ships, aircrafts, and so forth, for example.
2. Description of the Related Art
A display device of this kind is disclosed in Japanese patent laying-open publication No. (Tokkaihei) 7-20794. This display device includes plural light emitting elements disposed in line, a polygonal column-like mirror with plural reflective surfaces, a lens to diverge light emitted from the light emitting elements, a drive unit to rotate the mirror, a screen to display two-dimensional image, and a controller to control light-on timing of the light emitting elements selectively according to a rotational position of the mirror.
The above known conventional display device, however, encounters a problem that the screen causes light energy loss much for displaying an image on driving information of motor vehicles, boats and ships, aircrafts, and the like, for example, because the screen diffuses the light. In order to settle this problem, a larger light source is needed. This brings the display device larger dimensions, increase in electric power consumption and heating value, expensive manufacturing cost, and life-cycle aggravation of light emitting elements.
It is, therefore, an object of the present invention to provide a display device which overcomes the foregoing drawbacks and can decrease light energy loss, its manufacturing and running costs, and its dimension with obtaining sufficient display-brightness.